Trimmer mechanism for sewing machines



Jan. 12, 1943, -F. PAR RY 2,308,470

I TRIMMER MECHANISMS FOR SEWING MACHINES Filed May 7,:1940 Sheets-Sheet 1 Mow,

F; PARRY Jab. 12, I943.

T RIMMER MECHANISMS'FOR SEWING MACHINES Filed May '7, 1940 4 Sheets-Sheet 2 i ILItKE Jan. 12, 1943.

F. PARRY 2,308,470 ..TRIMMER MECHANISMS FOR SEWING H'ACHINES Filed May '7, 1940 4 Sheets-Sheet 4 tion thereof.

Patented Jan. 12, 19 B 'ranvnunarmcnmsm m SEWING MACHINES Frank Parry, Bridgeport, Conn, assignor to The Singer Manufacturing Company, Elizabeth, N. .L, a corporation of New Jersey Application May 7,1940, Serial No. 333,707

17 Claims.

This invention relates to trimmer mechanisms for sewing machines and has for its primary object to provide improved means for controlling the effective action of trimmer-actuating mechanisms adapted to be thrown into and out of operation at will during the operation of the machine.

More specifically, an object of the invention is to provide a trimmer-knife actuating mechanism, which may be at will rendered ineilective without disconnecting the component elements of said actuating mechanism, with manually operable means for disabling andfor rendering effective the trimmer-knife actuating train of connections.

The invention has for a further object to provide a trimmer mechanism of sturdy construction particularly adapted to trim heavy work, in comin connection with the accompanying drawings which illustrate a preferred embodiment of the invention and in which:

Fig. l is a view in front side elevation and partly in vertical section of a portion of a sewing machine containing the improved trimmer mech anism. Fig. 2 represents a front end elevation of the sewing machine shown partly broken away. Fig.- -3 represents a top plan view of the trimmer mechanism, a part of the machine frame and the knife-bar being illustrated in horizontal section.

, Fig. 4 represents a cross-sectional view of the bracket-arm of the machine, substantially on the line 4-4 of Fig. l, and showing the trimmer rockshaft actuating connections in an operative posipartly in section, the trimmer-actuating connections illustrated in Fig. 4, but in the inoperative position of said connections. Fig. 6 represents a detail cross-section of the toggle-links and Fig. 5 shows in side elevation, and

spring-latch employed for actuating the trimmer rock-shaft. Fig. 7 represents in perspective, and

partly in section. the cooperating movable and stationary trimmer-knives and the supporting means therefor. Fig. 8 represents a bottom p an recessed in aside face thereof to provide a-seat view, partlyin horizontal sectionfof the'ledgerblade supporting bracket. Fig. 9 represents a horizontal section of the knife-holder guide-block and guideway in the plane of the axis of pivotal connection of the knife-bar actuating link with the guide-block.

The sewing machine illustrated-in the drawings has a frame including the usual work-supporting bed-plate l and overhanging bracket-arm 2 ter- I is a horizontally disposed main actuating shaft l carrying at one end a crank-disk 5. The crank- 'disk5 is provided with the usual crank-pin a connected by a link I with a vertically disposed needle-bar '8 journaled for endwise reciprocation in suitable bearings in the bracket-arm head 3. At its lower end, the needle-bar 8 carries an eyepointed needle 9.

Complemental to the of lock-stitches is a horizontal-axis rotary looptaker I0 disposed below the bed-plate l and adapted to cast needle-thread loops about a thread-carrier ll journaled in and suitably. re-. strained against rotation with said loop-taker. The loop taker i0 may be actuated in any suitable manner and it is to be understood that any other preferred form of stitch-forming mechanism may be substituted for that contained in the present sewing machine.

The work may be advanced 'past the stitchforming mechanism by any usual or suitable feeding mechanism, the present machine having for that purpose a'feed-dog l2 of the drop-feed type. The feed-dog I2 is opposed by a presser-foot l3 secured to the lower end of a spring-depressed presser-bar I4 which is endwise movable'vertically in suitable bearings provided in the bracket-arm head 3.

Thepresent invention relates more particularly to the trimmer mechanism embodied in the sewing machine referred to and including a vertically movable trimmer-knife IS. The trimmer-knife I5 is angular in cross-section, having a pilot-wing l6 depending vertically from a lateral cutterwing ll substantially normal to thepilot-wing l6, and an attaching rib l8 rising vertically from the cutter-wing ll. The trimmer-knife I5 is lengthwise inclined to the work-support l, the effective end of the pilot-wing 16 being vertically disposed and the adjacent end portion of the cutter-wing I1 providing a cutting-edge II.

The trimmer-knife i5 is carried by a vertically disposed knife-holder plate l9 which is suitably needle 9 in the formation for one side and the upper edge of the attachingrib l8 of the knife. The opposite face of the attaching-rib l 8 of the knife is engaged by a clampplate 28 secured to the knife-holder plate I!) by a screw 2|, said clamp-plate 28 being recessed to receive the cutter-wing I1 of the knife, whereby the trimmer-knife I is rigidly but endwise adjustably secured to the knife-holder plate Ill.

The knife-holder plate I9 is carried by the lower end of a vertically disposed knife bar 22 journaled for endwise movement in a vertically apertured bushing 23. The bushing 23 is secured by screws 24 in a frame-boss 25 provided at the front side of the bracket-arm head 3.

The bushing 23 extends below the frame-boss 25, and clamped to the projecting portion of said bushing 23, by a screw 26, is the split-hub of a guide-frame holder 21. Secured by a screw 21' to the holder 21 is a vertically depending guideframe 28, which is channeled to provide a lengthwise vertically extending and forwardly open guideway 29, in which is slidingly disposed the split end portion 38 of a guide-block 3| extending rearwardly from and preferably integral with the, knife-holder plate IS. A tapered screw 32 threaded into the split-end portion 38 of the guide-block provides for adjustably spreading said portion 38. thereby to take up wear, the screw 32 being accessible through a suitable aperture 33 provided in the rear wall of the, guideway 28. 1

Connected to the guide-block 3| by a pivotbolt 34 is the lower end of a link 35 disposed adjacent to the frame-boss 25, the upper end of said link being connected by a pivot-bolt 36 to a crank-arm 31 extending forwardly from and having a split hub clamped upon one end of a knife-actuating rock-shaft 38. The rock-shaft 38 is journaled horizontally in bushings 39 and 48 secured, respectively, in spaced bearing-lugs 4| and 42 depending from a supporting bracket 43, said bracket 43 being secured 'by screws 44 to the flattened under side of the bracket-arm 2.

The bushing 48 and the rock-shaft 38 journaled therein extend through an aperture 45 in a depending portion of the wall of the bracket-arm 2 adjacent the bearing-lug 42 of the supporting bracket 43, and the front wall of the bracket-arm 2 is provided with an opening 46 closed by an inwardly flanged cover-plate 41. detachably secured to the bracket-arm 2 by screws 48.

Clamped by a screw 48 upon the end of the rock-shaft 38 within the bracket-arm 2 is the split hub of a forwardly extending crank-arm 58. The free end of the crank-arm 58 is connected by a pivot-bolt 5| to one end of a lower togglellnk 52. At its opposite end, the toggle-link 52 has a fork 53 receiving the lower end of a complemental or upper toggle-link 54 connected to the link 52 by a pivot-pin 55 disposed substantially parallel to the pivot-bolt 5|. The upper toggle-link 54 has a split strap 58 embracing an actuating element in the form of an eccentric 51. carried by the actuating shaft 4, and the lower end of said link 54 has an offset extension 54' adapted to engage the rearward side of the toggle-link '52 in the toggle-straightened or operative position of said links, A spring-latch 56 .(Fi'g. 6) is secured byscrews 58 to the togglelink 52 in position to engage the extension 54' of the link 54, thereby to ,hold the links 52, 54

- releasably in the toggle-straightened position thereof.

It will be understood from the foregoing detoggle links 52, 54, are disposed in parallelism with the axis of rotation of the bracket-arm shaft 4. It will be further understood that in the alined or toggle-straightened position of the links 52, 54, illustrated in Fig. 4 of the drawings and releasabiy maintained by the spring-latch '58, the two links together function as a pitman to transmit oscillatory movements to the rockshaft 38, thereby vertically reciprocating the knife-bar 22 and imparting work-severing movements to the trimmer-knife I5.

Disposed substantially parallel to the rockshaft 38, at the rear side of the bracket-arm 2 and journaled in suitable bearings, of which one is in the present case provided by the lug 42, is a controller rock-shaft 68. Suitably secured to said controller rock-shaft 68 is a crank-arm 6| extending forwardly through an opening 62 provided in the rear wall of the bracket-arm 2, said crank-arm having its forward free end disposed within the bracket-arm 2 and connected as by a chain 63 to a suitable treadle or knee-shift device (not shown). A spring 64 is anchored to a post 65 at the rear side of the bracket-arm 2 and bears against the crank-arm 6| in a direction to bias said crank-arm upwardly.

Secured to the controller rock-shaft 68, by a clamp-screw 68, is the split-hub of a togglestraightening arm 61 extending forwardly from the rock-shaft through an opening 68 in the rear wall of the bracket-arm 2. The forward or free end of the toggle-straightening arm 61 is adapted to engage the rear face of the upper togglelink 54 adjacent to the knuckle of the links 52, 54, in the toggle-broken position 'of said links illustrated in Fig. 5 of the drawings. By depressing the treadle-actuated arm 6| of the rock-shaft 68, against the action of the spring 64, the rockshaft 68 is actuated to cause the arm 61 to engage the toggle-link 54 and thereby to bring the links 52, 54 into alined or toggle-straightened position thereof wherein the two links are releasably connected together by the spring-latch 58. The crank-arm 6|, the rock-shaft 68 and the togglestraightening arm 61 together comprise a lever affording the requisite power to straighten the taggle links, thereby forcingthe trimmer-knife downwardly through work, when in cutting position upon the work-support.

'Also secured to the controller rock-shaft 68, by a clamp-screw 59, is the split-hub of a knifebar lifter arm 18.. The arm 18 extends forwardly from the rock-shaft 68 through the bracket-arm opening 68 and is bent downwardly and rearwardly about the crank-arm 58 into U-shape, whereby the rearwardly extending free end portion 18' of the arm 18 underlies the crank-arm 58 of the knife-actuating rock-shaft 38.

Attached by a pivot-bolt 1| to the downwardly formed in the bracket-arm cover-plate 41. The

outer end of the lever-arm 12 is preferably horizontally flattened to provide a finger-piece 12'.

The arm 13' of the toggle-breaking lever extends upwardly from the pivot-bolt II and, in the operative position of the toggle-links 52, 54, the free end of the arm 13 is positioned to imderlie and engage an angularlatch-plate 41' suitably secured to the cover-plate 41 to extend inwardly therefrom, thereby releasably latching the knifebar lifter-arm 18 in a positionthereof wherein the portion 18' of said lifter-arm is held spaced from the crank-arm 58. In order to maintain the lever I2, 13 releasably in the lifter-arm latching position thereof illustrated in Fig. 4 of the drawings, there is provided a spring 95 which engages the lever-arm l2 and biases said lever into a position wherein a stop-pin I carried by the lever-arm I3 engages a stop pin 18 carried \by the lifter-arm 10. At its upper free end, the lever-arm 13 has a rearwardly extending nose 13' adapted to engage thetoggle-link 52, adjacent or substantially at the knuckle of the links 52, 54, when the toggle-breaking lever 12, I3 is manually actuated by swinging the lever-arm l2 upwardly.

The lever-nose 13' is thereby caused to bear against the toggle-link 52, thus releasing the toggle-link 54 from the latch 58 and initiating under side of the crank-arm 50, thereby com- I pletin'g breaking of the toggle-links 52, 53 and, at the same time, turning the rock-shaft38 in a direction to raise the trimmer-knife l5 into an inoperative position thereof. position of the trimmer-knife I5 is determined in the present machine by the engagement of the knife-holder plate IS with the lower end of the knife-bar bushing 23. The eccentric 51 now idly actuates the toggle-links 52, 53, and the trimmer-knife l5 therefore remains stationary in its inoperative position until again thrown into operation by actuation of the controller rockshaft 80. 4 a Y While the rock-shaft 80 may be actuated by the described treadle connections therewith to straightened, as well as broken, by manual operation of the lever 12, I3.

The reciprocatory trimmer-knife l5 coacts The inoperative 85 thereof is threaded to receive a clamping-nut 81. The arrangement described provides for convenient adjustment of the ledger-blade 11 in a vertically inclined direction, the upper edge II of said ledger-blade being preferably slightly inclined upwardly toward the rearward edge thereof. The ledger-blade I1 is positioned so that the end of the pilot-wing l8 of the reciprocatory trimmer-knife l5 slidingly engages the adjacent side face of the ledger-blade 11, whereby the coacting blades are relatively properly positioned to effect work-severing coaction of the cuttingedge ll of the knife l5 with the proximate upper. edge 11' of the ledger-blade.

In the present machine a transverse binder 88 (is disposed between the trimming zone andthe needle, and it is therefore desirable to divert the trimmed-off margin of the work immediately at the trimming zone. To this end, a deflectorplate 89 is secured to the reciprocatory knifeholder by the knife-clamping plate securing screw 2|, the lower edge of said deflector-plate 89 descending slightly below the upper face of the bed-plate I during the work-severing operation and thereby crowding the trimmed-oil workmargin downwardly through an opening 90 in the bed-plate l.

Secured by a screw 9| to the ledger-blade bracket-flange 80 is a depending ear 92 of a chute 93 disposed in the bed-plate opening 90 and inclined downwardly in a direction away from the bracket-flange 88. The front and rearward end portions of the chute 93 are bent upward-1y to provide ears or flanges 94 which serve as side guides directing the trimmed-off workmargins downwardly along and off the free edge of the chute, where said trimmed-01f work-mar:- gins are free to fall through the bed-plate opening 90 without fouling the actuatingmechanism of the sewing machine.

Having thus set forth the nature of the invention what I claim herein is: 3.:

1. In a trimmer mechanism for sewing m'achines comprising, an actuating element, a trimmer-knife carrier, and an operative train of connections for actuating said carrier from said element including a pairof toggle-links relatively movable into and out of toggle-straightened operative position, the improvement which consists with a stationary ledger-blade I1 lengthwise inclined vertically and widthwise disposed substantially parallel to the line of seam formation.

The

adjustably disposed in a corresponding recess in the under side of the bed-plate l, the described arrangement providing for adjustment of the bracket 18 crosswise of the line of scam formation. The bracket-flange is provided in its outer face with a-'vertically inclined channel 84 re;

ceiving the ledger-blade 11, the latter being clamped against the flange 80 by the laterally notched head of a securing-pin 88. The securing-pin 88 passes through suitable guideapertures in the bracket-flanges I9 and 80, and the end of the securing-pin opposite to the head in the provision of a normally stationary and manually operable toggle-breaking member disposed for engagement with said toggle-links in the toggle-straightened position of said links.

2. In a trimmer mechanism for sewing ma chines comprising an actuating element, a trimmer-knife carrier, and an operative train of connections for actuatingsaid carrier from said element including a pair of toggle-links relatively movable into and out of toggle-straightened operative position, the improvement which consists in the provision of a normally stationary and manually operable toggle-straightening member disposed for engagement with said toggle-links in the toggle-broken position of said links. I

'3. In a trimmer mechanism for sewing machines comprising, an actuating element, a-trimmer-knife carrier, and an operative train of connections for actuating said carrier from said element including a pair of toggle-links relatively movable into and out of toggle-straightened operative position, the improvement which consists in the provision of normally stationary means actuable for straightening and for buckling said toggle-links.

4. In a trimmer mechanism for sewing machines comprising an actuating element, a trimmer-knife carrier, and an operative train of connections for actuating said carrier from said element including a pair of toggle-jointed links, the improvement which consists in the provision of manually operable means separate from said links for at will relatively moving said links into and out of toggle-straightened operative position thereof.

5. In a trimmer mechanism for sewing machines comprising an actuating element, a trimmer-knife carrier, and an operative train of connection for actuating said carrier from said element including a pair of toggle-jointed links, the improvement which consists in the provision of manually operable lever means engageable in opposite directions with said toggle-links for at will relatively moving said links into and out of toggle-straightened operative position thereof.

6. In a trimmer mechanism for sewing machines comprising, an actuating element, a trimmer-knife carrier, an operative train of connections for actuating said carrier from said element including a pair of pivotally jointed toggle-links, and releasable means for latching said togglelinks in toggle-straightened operative position, the improvement which consists in the provision of a lever engageable with said toggle-links in a direction transverse to the axis of pivotal connection of said links.

7. In a trimmer mechanism for sewing machines. comprising, an actuating element, a trimmer-knife carrier, an operative train of connections for actuating said carrier from said element including a pair of pivotally jointed toggle-links, and releasable means for latching said togglelinks in toggle-straightened 'operative'position. the improvement which consists in the provision j of-a lever engageable with said toggle-links in a direction to buckle said links and thereby to eflect release of said links from said latching means. and yielding means for normally maintaining said lever in ineffective position.

8. In a trimmer mechanism for sewing machines comprising, anactuating element, a trimmet-knife carrier, an operative train of connections for actuating said carrier from said element including a pair of pivotally jointed toggle-links. and releasable means for latching said togglelinks in toggle-straightened operative position, the improvement which consists in the provision of a lever engageable with said toggle-links in a direction to initiate buckling of said links and thereby to effect release of said links from-said latching means, and spring-biased means for completing buckling of said toggle-links into a position thereof inefictiveto actuate said trimmet-knife carrier. 1

9. In a trimmer l nechanism for sewing ma chines comprising, an actuating element, a trimmer-knife carrier, an operative train of connections for actuating said carrier from said element and releasable means for'latching said toggleing said arm and said lever in ineffective positions thereof.

v 10. In a trimmer mechanism for sewing machines comprising an actuating element, a trimmer-knife carrier, an operative train of connections for actuating said carrier from said element including a pairof pivotally Jointed toggle-links, and releasable means for latching said toggle-links in toggle-straightened operative position, the improvement which consists in the provision of a manually operable controller rock-shaft, and devices carried by said rockshaft' for relatively moving said toggle-links into and out of toggle-straightened operative position.

11. In a trimmer mechanism for sewing machines comprising, an actuating element,a trimmer-knife carrier, an operative train of connections for actuating said carrier from said element including a pair of pivotally jointed togglelinks, and releasable means for latching said toggle-links in toggle-straightened operative position, the improvement which consists in the provision of a' manually operable controller rock-shaft lengthwise disposed substantially parallel to the axis of pivotal connection of said toggle-links, an arm carried by said rock-shaft a manually operable toggle-breaking lever 'pivotally mounted upon said am and engageablawith said toggle-links in a direction to buckle said links, and a toggle-straightening arm carried by said rock-shaft for engagement with said toggle-linksin a toggle-broken position of said links. I

v 12. A trimmer mechanism for sewing machines comprising, a rotary actuating shaft, an actuating element carried by said shaft, a trimmerknife carrier, a knife-carrier actuating rockshaft, connections for actuatingsaid rock-shaft from said actuating element including a pair of comprising, a rotary actuating shaft, an actuating element carried by said shaft, a trimmerknife carrier, a knife-carrier actuating 'rockshaft disposed substantially parallel to said actuating shaft, 9.- crank-arm carried by said rock-shaft, pivotally Jointed toggle-links connecting said actuating element to said crankarm, the axis of pivotalconnection of said togglelinks being disposed substantially parallel to the including a pair of pivotally jointed toggle-links,

links in toggle-straightened operative position, 1 the-improvement which consists in the provision of means for disabling said toggle-links, said axis of rotation of said actuating shaft, releasable from said controller rock-shaft and adapted to engage said crank-arm in a direction to buckle said toggle-links, a manually operable toggleually operablelever pivotaly mounted upon said arm and engageable with said toggle-links in a direction to buckle said toggle-links, and means breaking lever pivotally mounted upon said liftingarm for initiating buckling of said togglelinks, releasable means formaintaining said toggle-breaking lever and lifting arm in ineffective position during operation of said trimmerknife carrier, and a toggle-straightening arm carried by said controller rock-shaft for engagement with said toggle-links in a toggle-broken position of said links. v

14. The combination in a sewing machine having a frame including a hollow bracket-arm, and a rotary actuating shaft journaled in said bracket-arm, of a trimmer mechanism comprising a trimmer-knife carrier, a rock-shaft dis-- posed substantially parallel to said actuating shaft and connected to actuate said knife-carrier, connections disposed within said bracketarm for actuating said rock-shaft from said rotary "actuating shaft including a pair of pivotally-jointed toggle-links, releasable means for maintaining said toggle-links in togglestraightened operative position thereof, and

means manually operable at will during the operation of the machine for buckling said toggle-links.

15. The combination in a sewing machine having a frame including a hollow bracket-arm, and a rotary actuating shaft journaled in said bracket-arm, of a trimmer mechanism comprising a trimmer-knife carrier, at rock-shaft disposed substantially parallel 'to said actuating shaft and connected to actuate said knife-carrier, connections disposed within said bracketarm for actuating -said rock-shaft from said rotary actuating shaft including a pair of pivotally-jointed toggle-links, releasable means for maintaining said toggle-links in togglestraightened operative position thereof, manually operable means at the front side of said bracketarm for buckling said toggle-links, a. manually link pivotally connected to said first named link and pivotally connected to said crank-arm, the

axes of said pivotal connections being disposed substantially parallel to the axis of rotation of said rotary actuating shaft, and means releasable at will during the operation of the machine for maintaining said links in a toggle-straightened operative position thereof.

17. In a trimmer mechanism for sewing machines, an actuating eccentric rotatable about I an axis, a trimmenknife carrier, a pitman comprising a pair of toggle-links pivotally connected together for movement relative to each other about anaxis substantially parallel to the axis of rotation of said eccentric, means for releasably latching said toggle-links in toggle-straightened relation thereof, one of said toggle-links having a strap embracing said eccentric to derive endwise and sidewise movements therefrom, and operative connections with the other of said toggle-links for actuating said carrier.

FRANK PARRY. 

